1. Technical Field
The present invention relates to a method and apparatus for rapidly screening and characterizing an array of materials. More particularly, this invention is directed to an optical technique for the parallel screening and characterizing of different materials in a combinatorial library.
2. Discussion
Combinatorial materials science refers generally to methods for creating a collection of chemically diverse materials or compounds and to methods for rapidly testing or screening such collections, commonly known as libraries, for desirable performance characteristics and properties. In recent years, the advent of combinatorial chemistry has revolutionized the process of drug discovery (see for example 29 Acc. Chem. Res. 1-170 (1996); 97 Chem. Rev. 349-509 (1997); S. Borman, Chem. Eng. News 43-62 (Feb. 24, 1997); A. M. Thayer, Chem. Eng. News 57-64 (Feb. 12, 1996); N. Terret, 1 Drug Discovery Today 402 (1996)). Researchers have also used combinatorial strategies in the discovery and optimization of materials, such as superconductors, zeolites, magnetic materials, phosphors, catalysts, thermoelectric materials, high and low dielectric materials and the like.
Although new and useful materials can be developed in less time using combinatorial methods, further efficiency gains can be achieved by improving the speed and efficiency of library screening. Once a combinatorial library is created, there looms the daunting task of identifying a handful of promising compounds or materials out of a combinatorial library comprising hundreds, thousands or perhaps millions of compounds or materials. While the use of combinatorial methods in synthesizing candidate compounds or materials speeds up the discovery process, testing the individual compounds or materials can consume a significant amount of time and resources.
Known analytical techniques are often unsuitable for screening combinatorial libraries because of poor sensitivities, slow response and the inherently serial nature of most instrumentation. The latter two difficulties can be overcome by adopting parallel measurement techniques, in which the same characterization method is applied to all elements in the library simultaneously. However, the ease with which this can be accomplished is strongly dependent on the specific nature of the technique utilized. Optically based methods possess a clear advantage in this regard in that parallel data collection and analysis is easily accomplished using preexisting imaging and image processing technologies. The optical characteristics of a compound or material reflect the electronic properties of the constituent molecules as well as the arrangement of these molecules in space, making it possible to detect changes in physical or chemical structure through optical means. One known application of such a method has been applied to screening selected characteristics of materials as a function of applied voltage (described in co-pending U.S. patent application Ser. No. 08/947,085 "Optical Systems and Methods for Rapid Screening of Libraries of Different Materials", published as WO 98/15805, which is incorporated herein by reference).
However, there exists a need for other apparatuses and methods for rapidly screening and characterizing, in parallel, the optical and physical properties of an array of compounds or materials.